TREES AND THEIR HEALTH IMPACTS
Trees are important to our health. In a July 26, 2019 article titled: MORE TREES MEAN BETTER HEALTH OUTCOMES, ACCORDING TO NEW RESEARCH Tom Jacobs writes that "New Australian research finds that, when a neighborhood's green space leads to better health outcomes, it's the canopy of trees that provides most of the benefits.... In recent years, study after study has found that living in neighborhoods with abundant green space is linked to positive health outcomes. These include better heart health, stronger cognitive development, and greater overall longevity. No wonder these areas are also linked to lower levels of Medicare spending. But when it come to promoting human health, not all green spaces are created equal. That's the conclusion of new Australian research, which finds higher levels of wellness in areas marked by one particular manifestation of the natural world: leafy trees. 'Protection and restoration of urban tree canopy specifically, rather than any urban greening, may be a good option for promotion of community mental health,' write Thomas Astell-Burt and Xiaoqi Feng of the University of Wollongong in New South Wales. Their study, along with a commentary, is published in the journal JAMA Network Open. They describe a large-scale longitudinal study featuring 46,786 mostly older residents of three Australian urban areas.
The subjects were initially interviewed between 2006 and 2009; follow-up reports were taken between 2012 and 2015. At both points, participants were asked to rate their overall health, and noted whether they have ever been diagnosed with, or treated for, anxiety or depression. In addition, they completed a 10-item questionnaire designed to measure their risk of psychological distress. Among other items, they noted how often in recent weeks they had felt 'hopeless, rigid, or fidgety,' 'so sad that nothing could cheer you up,' or 'worthless.' Researchers compared the participants' answers to the natural features of the "mesh block" where their home is located (a geographical unit containing 30 to 60 dwellings). Using satellite imagery, the team calculated both the percentage of total green space and "separate green space types, including tree canopy, grass, or other low-lying vegetation. After taking into account such variables as the participants' age, gender, education, and household income, the researchers were able to confirm the results of previous studies, finding that "total green space appeared to be associated with lower odds of incident psychological distress. More intriguingly, they also found that exposure to low-lying vegetation was not consistently associated with any particular health outcome. Exposure to grass was, surprisingly, associated with higher odds of psychological distress. The wellness-boosting feature, then, appears to be the trees.
The researchers report that living in areas where 30 percent or more of the outdoor space is dominated by tree canopy was associated with 31 percent lower odds of psychological distress, compared to people living in areas with 0 to 9 percent tree canopy. 'Similar results were found for self-related fair to poor general health,' with tree-rich residents reporting better health overall, the researchers write. Astell-Burt and Feng can only speculate on the reasons behind their findings, but they come up with some reasonable guesses. 'Shorn of tree canopy, sidewalk temperatures can be higher, sidewalks can seem noisier, and walkers along them are exposed to more air pollution,' they write. In addition, they point to studies suggesting that 'higher levels of biodiversity, rather than the amount of green space, were associated with more favorable levels of psychological well-being.' Research shows that "tree canopy is more supportive of biodiversity than open grasslands,' they add. In an accompanying commentary, Dutch environmental researcher Sjerp de Vries cautions that these researchers are journeying into 'uncharted territory,' and suggests that a measure of per capita green space might be the best measure of its benefits. Additional research is clearly called for. Nevertheless, these results provide evidence of the benefits of natural shade, and suggest that our love of trees may be biologically driven. A neighborhood's leafiness is worth keeping in mind when you're deciding where to put down roots." READ the article here: https://psmag.com/news/more-trees-leads-to-better-health-outcomes-according-to-new-research
Unless the City Council majority feel that poor people in Cambridge deserve poorer development, health, and longevity than the rest of our citizens, then they must stop voting they way that they have most recently. Thanks to this group's votes, the cutting of mature trees is now permitted for affordable housing developments, while elsewhere in the city it has been banned. According to votes by this same City Council majority at the Ordinance Committee meeting last Thursday, current green space requirements in key parts of the city (places where trees will grow) will be limited in these same AHO developments to 7.5 feet on side yards - not enough space for mature trees to flourish, particularly once you add in bike sheds, dormers, and decks.
THE COOLING IMPACT OF TREES
And it is not just about one's health (rich or poor), this is also about the impacts of global warming and the fact that it is these same West Cambridge, District Nine, and Agassiz neighborhoods that provide much of the tree canopy that will be cut, but also that this part of the city is what cools off the rest of the city. The map below makes this perfectly eminently clear.
And we cannot just plant-a-new-tree every where in the city to get out of this problem in Cambridge. Not only does it take 30 or so years for a new tree to reach maturity but some 25% of newly planted trees die before they reach maturity. Furthermore, because we are so dense (between 3rd and 5th most dense city in the U.S. for populations over 100,000) we have very few spaces left to plant them. Again let's look at a map to see why. The map below shows the available permeable spaces in the city. There is VERY little of this land in many parts of the city outside of West Cambridge, Area 9 and Agassiz. So whether we care about trees because they are important to everyone's health (including the poor) or whether we care about trees because we need to address climate change now, the decisions Council is making regarding trees and green spaces in the AHO is critical to both the present and future of the city.
The AHO proposal to add massive and far taller buildings (such as the one below) everywhere in the city (and especially in the tree-rich areas of West Cambridge, Area 9, and Agassiz) will not only limit nearby residents to potential solar use, but also will limit our future for addressing sound environmental policy.
THE PROBLEMS WITH BIG DEVELOPMENTS EVERYWHERE
Yes we want and need more affordable housing housing here, even though we have far surpassed state mandates on this, but there are far better ways to achieve this by concentrating this housing on parts of our main corridors AND by rezoning to allow residents to add one or two new units within the shell of their current residences. When we see the scale of the structures being built now and even larger ones proposed for future the AHO projects "as-of-right" everywhere in the city, regardless of the destructive health and environmental impacts we see how problematic this city-wide up-zoning proposal is. We need to do this right!
Categories: AHO, Environment